更改 UICollectionView 数据源答案

【问题标题】：Changing UICollectionView DataSource更改 UICollectionView 数据源
【发布时间】：2016-07-20 20:22:20
【问题描述】：

我想在用户点击UISegment control 时更改CollectionView DataSource，但不知道如何实现。以下是部分代码：

查看控制器单元：

class ProjectsCollectionViewCell: UICollectionViewCell {

//MARK: - Public API
var project : Projects! {
    didSet {
        updateUI()
    }
}

private func updateUI() {
    titleLabel?.text! = project.title
    subTitleLabel?.text! = project.title
    featuredImageView?.image! = project.featuredImage

}

//MARK: - Private
@IBOutlet weak var featuredImageView: UIImageView!
@IBOutlet weak var titleLabel: UILabel!
@IBOutlet weak var subTitleLabel: UILabel!

override func layoutSubviews() {
    super.layoutSubviews()

    self.layer.cornerRadius = 10.0
    self.clipsToBounds = true
}

}

View Controller 数据结构：

class Projects {

//MARK: - Public API

var title = ""
var subTitle = ""
var featuredImage: UIImage!

init(title: String, subTitle: String, featuredImage: UIImage!) {

    self.title = title
    self.subTitle = subTitle
    self.featuredImage = featuredImage
}

//MARK: - Private

static func showProjectInfo() -> [Projects] {
    return [
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "1")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "2")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "3")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "4")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "5")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "6")!)
    ]
}

static func showWebInfo() -> [Projects] {
    return [
        Projects(title: "DA", subTitle: "SPASIBO", featuredImage: UIImage(named: "1")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "2")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "3")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "4")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "5")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "6")!)
    ]
}

static func showDeymInfo() -> [Projects] {
    return [
        Projects(title: "DA", subTitle: "PODJALUISTA", featuredImage: UIImage(named: "1")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "2")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "3")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "4")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "5")!),
        Projects(title: "DA", subTitle: "PRIVET", featuredImage: UIImage(named: "6")!)
    ]
}

}

视图控制器：

class ProjectsVC: UIViewController {

@IBOutlet weak var headerAlpha: UIImageView!

@IBOutlet weak var backgroundImage: UIImageView!
@IBOutlet weak var collectionView: UICollectionView!

//MARK: - UICollectionView DataSourse
private var projects = Projects.showProjectInfo()
private var web = Projects.showWebInfo()
private var deym = Projects.showDeymInfo()


override func viewDidLoad() {
    super.viewDidLoad()
    self.headerAlpha.backgroundColor = UIColor(red: 21/255, green: 55/255, blue: 80/255, alpha: 0.95)
}

//MARK: - CollectionView Data Sourse

private struct Storyboard {
    static let Cellidentifier = "Project Cell"
}

@IBAction func showComponent(sender: UISegmentedControl) {


}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController!.navigationBar.topItem!.title = "";

}
}

UICollectionView 数据源，委托：

extension ProjectsVC: UICollectionViewDataSource {

func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    return 1
}

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

    return projects.count
}

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(Storyboard.Cellidentifier, forIndexPath: indexPath) as! ProjectsCollectionViewCell

    cell.project = self.projects[indexPath.item]
    return cell

}
}

【问题讨论】：

你只改变projects的数据和collectionView的reloadData

标签： ios swift uicollectionview datasource uisegmentedcontrol

【解决方案1】：

这里有答案

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

    var returnValue = 0

    switch (mySegmentControl.selectedSegmentIndex) {
    case 0:
        returnValue = projects.count
    case 1:
        returnValue = web.count
    case 2:
        returnValue = deym.count
    default:
        break
    }

    return returnValue
}

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(Storyboard.Cellidentifier, forIndexPath: indexPath) as! ProjectsCollectionViewCell

    switch (mySegmentControl.selectedSegmentIndex) {
    case 0:
        cell.project = self.projects[indexPath.item]
    case 1:
        cell.project = self.web[indexPath.item]
    case 2:
        cell.project = self.deym[indexPath.item]
    default:
        break
    }

    return cell

}

}

【讨论】：

【解决方案2】：

您可以使用 switch 来检测选定的段索引，然后您可以根据需要分配数据源。

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

  //use switch here and call one of your methods (showWebInfo(),showProjectInfo() etc) like  projects = showProjectInfo()

    return projects.count
}

同样的事情你必须在：

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(Storyboard.Cellidentifier, forIndexPath: indexPath) as! ProjectsCollectionViewCell

     //use switch here and call one of your methods (showWebInfo(),showProjectInfo() etc) like  projects = showProjectInfo()

        cell.project = self.projects[indexPath.item]
        return cell

    }

【讨论】：

【解决方案3】：

你没有调用 reload CollectionView 从数据源加载数据。

override func viewWillAppear(animated: Bool) {
  super.viewWillAppear(animated)
  self.navigationController!.navigationBar.topItem!.title = "";
  collectionView.reloadData() 
}

【讨论】：

目前我没有什么要重新加载的:)
我没有看到你的代码中实现了 UISegment 控件。创建一个分段控件，并且分段在您重新加载 collecitonView 的函数中具有委托属性。

【解决方案4】：

UICollectionView 对象具有dataSource 属性，因此您可以轻松更改它。请记住，数据源必须采用UICollectionViewDataSource protocol。

【讨论】：